know (your) stuff

informal

to know a lot about a subject, or to be very good at doing something.

When it comes to restoring grand pianos, Mr Morley really knows his stuff.

• the toast of
• the toast of somewhere
• the tools of the trade
• the tools of trade
• the tools of your trade
• the top brass
• the top dog
• the top flight
• the top of the heap
• the top of the hour
• the top of the ladder
• make ready to do something
• make rounds
• make scarce
• make seem like a picnic
• make sense
• make sense of
• make sense of something
• make sheep's eyes at
• make sheep's eyes at someone
• make short work of
• make short work of someone
• make short work of something
• make sick
• make sit up and take notice